Inflammatory bowel disease (IBD) is a collective term used to describe related inflammatory disorders of the gastrointestinal tract whose etiology is not completely understood. The two most common forms of IBD are ulcerative colitis (UC) and Crohn's disease (CD). For most patients, IBD is a chronic condition with symptoms lasting for months to years. The course of IBD varies widely, with intermittent periods of remission (i.e., inactive disease) followed by periods of acute illness (i.e., active disease). Onset of IBD is predominant in young adulthood but can occur at any age.
Ulcerative colitis affects the large intestine (colon) and rectum and involves the inner lining (e.g., the mucosal and sub-mucosal layer) of the intestinal wall. Crohn's disease may affect any section of the gastrointestinal tract (e.g., mouth, esophagus, stomach, small intestine, large intestine, rectum, anus, etc.) and may involve all layers of the intestinal wall. The clinical symptoms of IBD include rectal and/or intestinal bleeding, abdominal pain and cramping, diarrhea, and weight loss. In addition, IBD is a risk factor for colon cancer, and this risk for colon cancer increases significantly after eight to ten years of IBD.
IBD has no cure. Current therapies for IBD are directed at reducing the inflammatory process and at reducing the detrimental effects of the inflammatory process associated with the disease, and include administration of anti-inflammatory drugs (e.g., mesalamine, sulfasalazine, infliximab, adalimumab, prednisone, budesonide) and of immunosuppressive drugs (e.g., 6-mercaptopurine, azathioprine, cyclosporine). Such therapies are often associated with adverse side effects, such as nausea, vomiting, anorexia, dyspepsia, malaise, headaches, abdominal pain, fever, rash, pancreatitis, bone marrow suppression, formation of antibodies, infusion reactions, and increased opportunistic infections. In severe cases of IBD, or when drug therapy fails to relieve the symptoms of IBD, surgical procedures, including colectomy, proctocolectomy, and ileostomy, are used. Unfortunately, the available methods for treating IBD provide only treatment of symptoms rather than a substantial cure. These methods include either drug therapy accompanied by severe adverse side effects or invasive surgical treatments that further affect the patient's quality of life and, in addition, may further be life threatening.